You can get the Ninja and pipe combo for under $400. Can't go wrong and the engine screams.
I think you can get the MR-12 T01AK from Kamikaze racing for $329 plus shipping. Or you might also wanna try the Picco JLR .12 Red Dot for $179.00 plus shipping engine only. Either way you can't go wrong they're both very good engines without the high costs.